Successive discounts of $10 \%$,$20 \%$ and $50 \%$ will be equivalent to a single discount of .......... $\%$

$A$ man purchases some oranges at the rate of $3$ for $₹ 40$ and the same quantity at $5$ for $₹ 60$. If he sells all the oranges at the rate of $3$ for $₹ 50$,find his gain or loss percent (to the nearest integer).

After selling $5 \%$ of a quantity of sugar,$5 \text{ kg}$ of sugar remains. Find the total quantity of sugar in $\text{kg}$.

Meenal purchased a car for $Rs. 2,50,000$ and sold it for $Rs. 3,48,000$. What is the percent profit she made on the car?

By selling an article for $Rs. 450$,a man loses $10\%$. The gain or loss percent if he sells it for $Rs. 540$ is:

$A$ man loses $20 \frac{1}{2} \%$ of his money and after spending $80 \%$ of the remainder,he is left with $Rs. 159$. How much did he have at first? (in $Rs.$)